Asymmetrical benzotriazolylphenols

ABSTRACT

Provided are asymmetrical, ultraviolet stabilizers which are hydroxyphenyl benzotriazolylphenol compounds of the formula: ##STR1## wherein: R 1  is C 1  to C 18  alkyl, C 6  to C 10  aryl, C 7  to C 16  arylalkyl, C 1  to C 12  alkoxy, C 6  to C 10  aryloxy, C 7  to C 16  arylalkoxy, cyclopentyl, cyclohexyl or cumyl; 
     R 2  is C 1  to C 18  alkyl, C 6  to C 10  aryl, C 7  to C 16  arylalkyl, C 1  to C 12  alkoxy, C 6  to C 10  aryloxy, C 7  to C 16  arylalkoxy, cyclopentyl, cyclohexyl or cumyl; 
     R 1  is different from R 2  ; and 
     X is selected from the group consisting of hydrogen, halogen, C 1  to C 12  alkyl, and C 1  to C 12  alkoxy. The invention also pertains to a process for their preparation and stabilized polymer blends containing the stabilizers.

BACKGROUND OF THE INVENTION

The present invention pertains to ultraviolet light stabilizers forplastics and coating compositions, or more particularly, to novel typesof compounds which are asymmetrical benzotriazolylphenols.

It is well known in the art that plastics are unstable over time uponexposure to ultraviolet light. Such plastics undergo a decrease inmechanical strength and an increase in unwanted color when exposed to uvradiation. It is also known to improve the resistance of plastics andcoating compositions to deterioration by the addition of a uv lightabsorber. Such commonly used stabilizers include compounds of thehydroxyphenyl benzotriazole family, including hydroxyphenylbenzotriazole monomers and dimers. Hydroxyphenyl benzotriazole monomersare well known in the art and are disclosed in earlier U.S. Pat. Nos.3,204,896; 3,189,6515; 5,097,041; 4,943,637 and 5,104,992. Hydroxyphenylbenzotriazole dimers are also known.

The benzotriazole dimers have an advantage over the monomericbenzotriazole u.v. absorbers. The dimers have higher molecular weightwhich makes them much less volatile. This is very important consideringthe high temperatures required for the processing of engineeringplastics. In addition, these dimers possess high thermal stability sothey are not decomposed when exposed to elevated temperatures forprolonged periods of time.

Benzotriazole type u.v. absorbers, including dimers, function through amechanism involving the phenolic hydrogen and the nitrogens of thetriazole ring. In attempts to reduce the volatility of benzotriazolemonomers, various organic groups were added to the phenolic ring and/orhalogens to the benzene ring of the benzotriazole. Volatility wasusually reduced by substitution of one or two organic groups on thephenolic ring. While these measures did improve the volatility problem,it also reduced the total u.v. absorption capability of thebenzotriazole monomers. Most commercial benzotriazoles which areavailable today are disubstituted.

U.S. Pat. Nos. 4,684,679, and 4,812,498 disclose the symmetrical dimers2,2'-methylene-bis-(4-hydrocarbyl-6 benzotriazolylphenols). U.S. Pat.Nos. 4,684,679 and 4,937,348 disclose a process for preparing thesymmetrical dimers 2,2'-methylene-bis-(4-hydrocarbyl-6-benzotriazolylphenols) by first formingthe Mannich base of a described benzotriazole monomer and then reactingthe Mannich base with the same benzotriazole monomer or the same Mannichbase. All of the above patents are incorporated herein by reference.Indeed, a common feature of all known benzotriazole dimers is that theyare symmetrical, that is, all units of the dimer or polymer contain thesame single hydroxyphenyl benzotriazole monomer unit. For example, U.S.Pat. No. 4,937,348 shows a hydroxyphenyl benzotriazole dimer having theformula: ##STR2## These compounds are symmetrical because each R₂, whichis an alkyl group having 1-18 carbon atoms at the 4 position of each ofthe phenolics, is identical. To synthesize benzotriazole dimers, one islimited to benzotriazole compounds where there is but a singlesubstitution on the phenolic ring. Disubstitution on the phenolic ringprevents the formation of a dimer through a Mannich base or by any knownreaction. This fact limits the number of benzotriazole dimers to the fewmonosubstituted benzotriazoles commercially available.

This is disadvantageous because the physical properties of symmetricaldimers of hydroxyphenyl benzotriazoles have limited properties withregard to melting point, molecular weight, uv absorption distribution,particle migration, and polymer compatibility. Since there are so fewcompounds in this dimer group, it is often impossible to select asymmetrical hydroxyphenyl benzotriazole having the best combination ofproperties. For example, while it may be desired for a benzotriazole tohave a certain uv absorption characteristic or melting point, it may notbe compatible with the plastic of choice. It has now been unexpectedlyfound, that by independently varying the alkyl (hydrocarbyl) group atthe 4-position of the phenolic ring so that each half of the dimer has adifferent substitution, numerous dimers can now be synthesized. Themelting point, molecular weight, and uv absorption distributionproperties can be tailored to the requirements for the polymer ofchoice. It has been found that each dimer half contributes itsbeneficial characteristics. Also unexpectedly, the melting points of theasymmetrical dimers are lower than one would normally expect. Thisallows the asymmetrical dimers to be used with polymers which areprocessed at lower temperatures and the lower melting point allowseasier dispersion in polymers.

It has also been unexpectedly found that in general, asymmetrical dimersdisplay higher solubility in organic non-polar solvents than symmetricaldimers made from the same monomers, as shown in Table 1 below. Thesymmetrical dimers usually have limited solubility in polar andnon-polar solvents and have higher melting points. With bettersolubility and lower melting point, asymmetrical benzotriazoles are moreeasily and more uniformly blended in the plastic to be stabilized. Theasymmetrical benzotriazoles make it possible to synthesize manydifferent combinations of monomers to form dimers with tailor madecharacteristics.

SUMMARY OF THE INVENTION

The invention provides an asymmetrical hydroxyphenylbenzotriazolylphenol compound having the formula: ##STR3## wherein: R₁is C₁ to C₁₈ alkyl, C₆ to C₁₀ aryl, C₇ to C₁₆ arylalkyl, C₁ to C₁₂alkoxy, C₆ to C₁₀ aryloxy, C₇ to C₁₆ arylalkoxy, cyclopentyl, cyclohexylor cumyl;

R₂ is C₁ to C₁₈ alkyl, C₆ to C₁₀ aryl, C₇ to C₁₆ arylalkyl, C₁ to C₁₂alkoxy, C₆ to C₁₀ aryloxy, C₇ to C₁₆ arylalkoxy, cyclopentyl, cyclohexylor cumyl;

R₁ is different from R₂ ; and

X is selected from the group consisting of hydrogen, halogen, C₁ to C₁₂alkyl, and C₁ to C₁₂ alkoxy.

The invention also provides a stabilized polymer composition whichcomprises a polymeric compound such as polycarbonates and theircopolymers, polyacrylates and their copolymers, polyacetals,polystyrenes, polyacrylonitrile, polydienes, polyesters, polyamides,polyurethanes, acrylonitrile-butadiene-styrene resins, polyphenylenesulfides, fluorinated polymers, polyolefins, acrylonitrile polymers andcopolymers, vinyl polymers and copolymers, vinylidene polymers andcopolymers, polyvinylacetate and its copolymers, and cellulosicpolymers, and from about 0.1% to about 5 % based on the weight of thepolymeric composition of the above asymmetrical hydroxyphenylbenzotriazolylphenol.

The invention further provides a process for the preparation ofasymmetrical hydroxyphenyl benzotriazolylphenols having the formula:##STR4## which comprises:

a.) reacting a 4-hydrocarbyl-6-benzotriazolylphenol having the formula:##STR5## with an amine having the formula HNR₃ R₄ and formaldehyde in anorganic solvent to produce a Mannich base having the formula: ##STR6##and

b.) reacting the Mannich base with a 4-hydrocarbyl-6benzotriazolylphenolhaving the formula ##STR7## in the presence of an alkaline catalyst,wherein: R₁ is C₁ to C₁₈ alkyl, C₆ to C₁₀ aryl, C₇ to C₁₆ arylalkyl, C₁to C₁₂ alkoxy, C₆ to C₁₀ aryloxy, C₇ to C₁₆ arylalkoxy, cyclopentyl,cyclohexyl or cumyl;

R₂ is C₁ to C₁₈ alkyl, C₆ to C₁₀ aryl, C₇ to C₁₆ arylalkyl, C₁ to C₁₂alkoxy, C₆ to C₁₀ aryloxy, C₇ to C₁₆ arylalkoxy, cyclopentyl, cyclohexylor cumyl;

R₁ is different from R₂ ;

R₃ and R₄ are selected from the group consisting of hydrogen, C₁ to C₆alkyl, and groups where R₃ and R₄ taken together form a four to sixmember heterocyclic ring including a nitrogen atom, provided that atleast one of R₃ and R₄ is not hydrogen; and

X is selected from the group consisting of hydrogen, halogen, C₁ to C₁₂alkyl, and C₁ to C₁₂ alkoxy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the practice of the present invention one begins with a hydroxyphenylbenzotriazole monomer of the formula ##STR8## wherein R₁ is C₁ to C₁₈alkyl, C₆ to C₁₀ aryl, C₇ to C₁₆ arylalkyl, C₁ to C₁₂ alkoxy, C₆ to C₁₀aryloxy, C₇ to C₁₆ arylalkoxy, cyclopentyl, cyclohexyl or cumyl and X isselected from the group consisting of hydrogen, halogen, C₁ to C₁₂alkyl, and C₁ to C₁₂ alkoxy. Benzotriazole monomers may be prepared byany method known in the art including those taught in U.S. Pat. Nos.5,097,041, 4,943,637 and 5,104,992. 2-aryl-2H-benzotriazoles monomersmay be produced by reducing o-nitroazobenzenes through a2-phenylbenzotriazole-N-oxide intermediate. A wide variety of reductiontechniques is known. Reduction of o-nitroazobenzenes to2-phenylbenzotriazole by zinc in the presence of sodium hydroxide isdisclosed in U.S. Pat. Nos. 3,018,269; 3,230,194; 3,773,751; 4,041,044;and 4,224,451. Reduction using aldehyde reducing agents and aromaticketone catalysts is disclosed in U.S. Pat. No. 4,835,284. Reductionusing saccharides and an aromatic ketone catalyst is disclosed in U.S.Pat. No. 4,780,541. All of these patents are incorporated herein byreference. These show methods for the preparation of benzotriazoles byreductive cyclization of azo dyes with saccharides in the presence ofaromatic ketone catalysts, which act by receiving hydrogen from thereducing agent and giving hydrogen to a material to be reduced. In eachof these cases, saccharide reduction is catalyzed by such aromaticketone catalysts as substituted and unsubstituted fluorenone.

The asymmetrical dimers of the present invention may be prepared by atwo step process including first forming the Mannich base of ahydroxyphenyl benzotriazole monomer, and then reacting the Mannich basewith another hydroxyphenyl benzotriazole monomer except the pendentgroup from the phenyl ring is a different group than is present on thehydroxyphenyl benzotriazole used above to form the Mannich base. TheMannich base is prepared by reacting the first hydroxyphenylbenzotriazole with a dialkyl amine and formaldehyde in an organicsolvent. The amines have the formula HNR3R₄ and non-exclusively includesecondary alkyl amines such as dimethylamine, diethylamine,di-n-propylamine, diisopropylamine, di-n-butylamine, di-t-butylamine,diisobutylamine, diamylamine, ethylmethylamine and ethylisopropylamine;and heteroalicyclic amines such as morpholine, piperidine andpyrrolidine. Formaldehyde or any of its polymeric forms can be used inthe process of the invention such as gaseous formaldehyde, aqueoussolutions of formaldehyde, paraformaldehyde, trioxane, trioxymethylene,tetraoxymethylene, and other solid polymers of formaldehyde.

Solvents useful for the process of the invention include essentially anyinert organic solvent that is a solvent for the reactants. It is alsocontemplated that solvents may be such as alcohols, ethers, hydrocarbonsand halocarbons, among others. These include alcohols such as methanol,ethanol, isopropanol, and n-butanol; hydrocarbons such as hexane,heptane, benzene, toluene, xylene, petroleum ethers, and mineralspirits, cycloaliphatic ethers such as furan, tetrahydrofuran anddioxane. The amount of solvent is not critical and can range from about50 to about 500 weight percent based on the amount of hydroxyphenylbenzotriazole. The amounts of amine and formaldehyde in the reactionwith the hydroxyphenyl benzotriazole in the solvent can bestoichiometric or slightly more and preferably each is in the range offrom about 1.0 to about 2.0 mole or more per mole of4-hydrocarbyl-6-benzotriazolylphenol. The Mannich base formationreaction can be carried out over a wide range of temperatures and ispreferably from about 60° C. to about 150° C., or more preferably fromabout 90° C. to about 110° C. In the preferred embodiment, the reactionis preferably conducted for from about 10 hours to about 30 hours, ormore preferably from about 20 hours to about 24 hours. The mostadvantageous reaction time may be determined by those skilled in theart.

The dimerization step is conducted by reacting the thusly producedMannich base with a stoichiometric amount of a4-hydrocarbyl-6-benzotriazolylphenol wherein the 4-hydrocarbyl group onthe phenol is a C₁ to C₁₈ alkyl group but is different from the C₁ toC₁₈ alkyl group on the 4-hydrocarbyl-6-benzotriazolylphenol used to formthe Mannich base. The dimerization reaction is preferably carried out inthe presence alcoholates of an alkaline catalyst. Such include loweralkali metal alcoholates such as sodium methylate and sodium ethylate,alkali metal hydroxides such as sodium and potassium hydroxide, andalkali metal alkaline salts such as potassium carbonate and sodiumcarbonate. The amount of catalyst is not critical and preferably rangesfrom about 0.001 to about 50 parts by weight, or more preferably fromabout 0.01 to about 8 parts by weight per 100 parts of hydroxyphenylbenzotriazole. The reaction can be carried out over a wide range oftemperatures and is preferably from about 120° C. to about 200° C., ormore preferably from about 150° C. to about 170° C. In the preferredembodiment, the dimerization reaction is conducted for from about 2hours to about 12 hours, or more preferably from about 3 hours to about10 hours. The most advantageous reaction time may be determined by thoseskilled in the art.

As hereinbefore mentioned, it is known in the art that plastics areunstable over time upon exposure to ultraviolet light. Such plasticsnon-exclusively include polycarbonates and their copolymers,polyacrylates and their copolymers, polyacetals, polystyrenes,polyacrylonitrile, polydienes, polyesters, polyamides, polyurethanes,acrylonitrile-butadiene-styrene resins, fluorinated polymers,polyolefins, acrylonitrile polymers and copolymers, vinyl polymers andcopolymers, vinylidene polymers and copolymers, polyvinylacetate and itscopolymers, and cellulosic polymers, among others. The uv stability ofsuch materials is improved by mixing the polymer with from about 0.1% toabout 5% based on the weight of the polymer composition of theasymmetrical dimer of this invention. The composition may be formed byheating the polymer to its softening point in an extruder and adding thedimer to the melt to form a substantially uniform physical mixture. Inthe method of the invention, the polymer materials which are generallythermoplastics or cellulosic, and the dimer are blended in the desiredquantities and heated to a temperature above the softening point of thepolymer. The heating and blending can be done in either order, however,in the preferred embodiment, these processes are conductedsimultaneously. The mixing may be conducted in any suitable equipmentincluding a Banbury mixer, single or twin screw extruder, ribbonblender, injection molding machine, two roll mill or the like, thusforming a substantially uniform blend of the plastic material and thedimer. The mixing step is usually conducted for from about 0.1 minutesto about 10 minutes at temperatures mostly dependent on the softeningpoint of the polymer being used. In the preferred embodiment, theheating is conducted at a temperature of from about 35° C. to about 350°C., or more preferably from about 100° C. to about 315° C., and mostpreferably from about 145° C. to about 300° C.

The asymmetrical hydroxyphenyl benzotriazoles of this invention can alsobe used as uv stabilizers for compositions such as organic coatings, andpaints when blended along with such additional components asantioxidants, plasticizers, fillers, heat stabilizers, solvents,colorants and processing aids. The following non-limiting examples serveto illustrate the invention.

EXAMPLE 1[2-Dipropylaminomethyl-4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenol

I. 323 g (1 Mole) of[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenol and 257 g(1.2 mole) of bis(dipropylamino) methane are dissolved in 500 ml ofbutanol-1 and the mixture is heated at reflux for 24 hours. The solventis vacuum distilled off and product crystallized from acetonitrile.Yield 414 g (95%). The melting point is 81.5° C.-83° C. and purity byHPLC is 99.8%.

II. 323 g (1 Mole) of[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenol, 42 g (1.4mole) of paraformaldehyde, and 303 g (3 mole) dipropylamine aredissolved in 500 ml of butanol-1 and the mixture heated at reflux for 20hours. The solvent is vacuum distilled off and product crystallized fromacetonitrile. Yield 98%. The melting point is 80° C.-82° C. and purityby HPLC is 99.5%.

III. 323 g (1 Mole) of[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenol, 39 g (1.3mole) of paraformaldehyde, and 303 g (3 mole) dipropylamine are heatedwith azeotropic removal of water and then the mixture is heated at 120°C.-125° C. for 20 hours. Dipropylamine is vacuum removed and the productcrystallized from acetonitrile. Yield 396 grams (91%). The melting pointis 81° C.-83° C. and purity by HPLC is 99.6%.

EXAMPLE 2[2-Dimethylaminomethyl-4-methyl-6-(2H-benzotriazol-2-yl)]phenol

I. A mixture of 225 g (1 mole) of[4-methyl-6-(2H-benzotriazol-2yl)]phenol, 248 g (2.2 mole) of 40%aqueous dimethylamine, 36 g (1.2 mole) of paraformaldehyde and 300 mlbutanol-1 is heated at 85° C. to 90° C. with gentle reflux for 20 hours.The mixture is cooled to 10° C. The product is crystallized fromacetonitrile to yield 211 g (75%). The melting point is 93° C.-97° C.and purity by HPLC is 99.2%.

II. A mixture of 225 g (1 mole) of[4-methyl-6-(2H-benzotriazol2-yl)]phenol, 248 g (2.2 mole) of 40%aqueous dimethylamine, 36 g (1.2 mole) of paraformaldehyde and 300 mlisopropanol is heated in an autoclave at 120° C. and 50 psi pressure for2 hours. The mixture is cooled to 10° C. The product is crystallizedfrom acetonitrile to yield 87%. The melting point is 94° C.-96° C. andpurity by HPLC is 99.4%.

EXAMPLE 3[2,2'-Dihydroxy-3,3'-di-(2H-benzotriazol-2-yl)-5-(1,1,3,3-tetramethylbutyl)-5'-methyl]diphenylmethane

I. 225 g (1 Mole) of 4-methyl-6-benzotriazol-2-yl-phenol, 20 g (0.5mole) of sodium hydroxide and 800 ml of pseudocumene are dissolved at90° C. to 95° C. and to this mixture is added 436 g (1 mole) of[2-dipropylaminomethyl-4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenoland the mixture is heated at 160° C. to 165° C. for 12 hours withconstant distillation of water and dipropylamine. Half of the solvent isvacuum distilled, 100 g of acetic acid are added and the mixture isheated at 130° C. to 135° C. for 15 minutes. 900 g of methanol areadded. The mixture is cooled to 10° C. and solid is filtered. Yield 532g (95%). The melting point is 178° C.-185° C. (DMF) and purity by HPLCis 90%.

II. 323 g (1 Mole) of[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)]phenol, 31.5 g(1.05 mole) of paraformaldehyde, 260 g of dipropylamine and 500 ml ofbutanol-1 are heated at reflux for 24 hours. The solvent is vacuumdistilled, 300 ml of pseudocumene are added and this mixture is added toa mixture of 4-methyl-6-benzotriazolylphenol 225 g (1 mole), sodiumhydroxide 20 g (0.5 mole) and 500 ml of pseudocumene which has beenpreheated to 90° C.-95° C. The mixture is heated at 160° C.-165° C. for12 hours with constant distillation of dipropylamine. Half of thesolvent is vacuum distilled, 100 g of acetic acid are added and themixture is heated at 130° C. to 135° C. for 15 minutes. 900 g ofmethanol are added. The mixture is cooled to 10° C. and solid isfiltered. Yield 537 g (96%). The melting point is 177° C.-184° C. andpurity by HPLC is 91%.

EXAMPLE 4[2,2'-Dihydroxy-3,3'-di(2H-benzotriazol-2-yl)-5methyl-5'(1,1-dimethylethyl)]diphenylmethane

267 g (1 Mole) of [4-(1,1-dimethylethyl)-6-benzotriazol-2-yl]phenol, 20g (0.5 mole) of sodium hydroxide and 1000 ml of pseudocumene aredissolved at 150° C. to 155° C. with distillation of water. The mixtureis cooled to 120° C. and to this mixture are added 282 g (1 mole) of[2-dimethylaminomethyl-4-methyl-6-(2H-benzotriazol-2-yl)]phenol and themixture is heated at 165° C.-170° C. for 3 hours. During this timedimethylamine is eliminated from the reaction. Half of solvent is vacuumdistilled, 100 g of acetic acid are added and the mixture is heated at130° C.-135° C. for 15 minutes. 900 g of methanol are added. Yield 428 g(85%). The product is crystallized from methylcellosolve. The meltingpoint is 216° C. to 219° C. Purity by HPLC is 96%.

EXAMPLE 5[2,2'-Dihydroxy-3,3'-di-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-5'-(1,1,3,3-tetramethylbutyl)]diphenylmethane

267 g (1 Mole) of 4-(1,1-dimethylethyl)-6-benzotriazol-2-yl-phenol, 20 g(0.5 mole) sodium hydroxide and 800 ml of pseudocumene are dissolved at90° C. to 95° C. and to this mixture are added 436 g (1 mole) a[2-dipropylaminomethyl-4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2yl)]phenoland the mixture is heated at 160° C. to 165° C. for 12 hours withconstant distillation of water and dipropylamine. Half of solvent isvacuum distilled, 100 g of acetic acid was added and the mixture isheated at 130° C. to 135° C. for 15 minutes. 900 g of methanol areadded. The mixture is cooled to 5° C. and oil is precipitated. Solventsare decanted, methyl cellosolve is added, the mixture is heated toreflux and filtered from some insolubles. Yield 271 g (38%), M.P.220°-222° C. and purity by HPLC is 88%.

EXAMPLE 6 (COMPARATIVE) Reaction of the mixture of 4-methyl- and4-t-octyl-6-benzotriazol-2-yl-phenols with paraformaldehyde

A mixture of 22.5 g (0.1 mole) of 4-methyl-6-benzotriazol-2-yl-phenol,32.3 g (0.1 mole) of 4-t-octyl-benzotriazol-2-yl-phenol, 25 g ofdipropylamine and 3 g (0.1 mole) of paraformaldehyde is heated at 140°C.-150° C. with azeotropic removal of H₂ O and dipropylamine. Then 60 gof pseudocumene and 0.9 g of NaOH are added and the mixture is heated at160° C. for 10 hours. Half of the solvent is vacuum distilled. 20 g ofacetic acid is added and the mixture heated at 130° C.-135° C. for 15minutes and 200 g of methanol is added. An oily product is precipitated.According to HPLC, the oil contains a mixture of four products:symmetrical methyl derivatives--46%, symmetrical 4-octylderivatives--24%, asymmetrical methyl-t-octyl derivatives--22% and 8%starting materials. This example shows that an attempt to form a dimerfrom 4-methyl-6-benzotriazol-2-yl-phenol and4-t-octyl-benzotriazol-2-yl-phenol by direct condensation forms anundesirable mixture.

EXAMPLE 7

The following table compares the properties of two hydroxyphenylbenzotriazole monomers, their symmetrical dimers and an asymmetricaldimer of them. These data show that the asymmetrical dimer has a lowermelting point than symmetrical dimer made from the same two startingmonomers. The asymmetrical dimer is much more soluble in the non-polarsolvent (pseudocumene) than either of the symmetrical dimer made fromthe same two starting monomers. The last two columns indicate that thereis no significant difference in absorbance of uv light comparing theasymmetrical dimer to the symmetrical dimers made from the same twostarting monomers.

                                      TABLE 1                                     __________________________________________________________________________                                     SOLUBILITY IN SOLVENTS                                                        (POLAR AND NON-POLAR)                                                         AT 25° C., IN GRAMS                                                    PER 100 GM. SOLVENT                                                                   ACETO-                                                          MELTING                                                                             METHANOL                                                                              NITRILE                                                 MOLECULAR                                                                             POINT (POLAR) (POLAR)                              COMPOUND    TYPE   WEIGHT  °C.                                                                          (PROTONIC)                                                                            (APROTONIC)                          __________________________________________________________________________    2-(2'H-Benzotriazol-2'-                                                                   Monomer                                                                              225     128-132                                                                             0.1     0.8                                  yl)-4-methylphenol                                                            2-(2'H-Benzotriazol-2'-                                                                   Monomer                                                                              323     103-104                                                                             0.5     0.8                                  4-t-octylphenol                                                               2,2'-Methylene-Bis-[6-                                                                    Symmetrical                                                                          462     280-285                                                                             insoluble                                                                             insoluble                            (2H-benzotriazol-2-yl)-                                                                   Dimer                                                             4-methylphenol]                                                               2,2'Methylene-Bis-[6-                                                                     Symmetrical                                                                          658     194-196                                                                             1.2     1.0                                  (2H-benzotriazol-2-yl)-                                                                   Dimer                                                             4-t-Octylphenol)                                                              [2,2'-dihydroxy-3,3'-di-                                                                  Asymmetrical                                                                         560     178-185                                                                             0.1     0.1                                  (2H-benzotriazol-2-yl)-                                                                   Dimer                                                             5-t-octyl-5'-methyl]                                                          diphenylmethane                                                               __________________________________________________________________________                      SOLUBILITY IN SOLVENTS                                                        (POLAR AND NON-POLAR)                                                         AT 25° C., IN GRAMS                                                                    ABSORBANCE AT GAMMA                                           PER 100 GM. SOLVENT                                                                           MAX. AT SET                                                   DIMETHYL  PSEUDO-                                                                             CONCENTRATION                                                 FORMAMIDE CUMENE                                                                              CHLOROFORM                                                    (POLAR)   (NON- 0.02 MMOL/                                                                            0.03 MMOL/                          COMPOUND          (APROTONIC)                                                                             POLAR 1000 ML 1000 ML                             __________________________________________________________________________    2-(2'H-Benzotriazol-2'-                                                                         5.8       6.0   1.445 (340 nm)                                                                        0.484 (340 nm)                      yl)-4-methylphenol                1.249 (300 nm)                                                                        0.413 (300 nm)                      2-(2'H-Benzotriazol-2'-                                                                         10.2      55.1  1.012 (340 nm)                                                                        0.480 (340 nm)                      4-t-octylphenol                   0.857 (300 nm)                                                                        0.439 (300 nm)                      2,2'-Methylene-Bis-[6-                                                                          0.1       0.1   1.429 (350 nm)                                                                        0.966 (350 nm)                      (2H-benzotriazol-2-yl)-           1.355 (305 nm)                                                                        0.912 (350 nm)                      4-methylphenol]                                                               2,2'Methylene-Bis-[6-                                                                           1.7       3.9   0.976 (350 nm)                                                                        0.963 (350 nm)                      (2H-benzotriazol-2-yl)-           0.969 (305 nm)                                                                        0.956 (305 nm)                      4-t-Octylphenol)                                                              [2,2'-dihydroxy-3,3'-di-                                                                        0.5       9.0   1.155 (350 nm)                                                                        0.947 (350 nm)                      (2H-benzotriazol-2-yl)-           1.116 (305 nm)                                                                        0.922 (305 nm)                      5-t-octyl-5'-methyl]                                                          diphenylmethane                                                               __________________________________________________________________________

What is claimed is:
 1. An asymmetrical hydroxyphenyl benzotriazolylphenol compound having the formula: ##STR9## wherein: R₁ is methyl;R₂ is octyl; and X is selected from the group consisting of hydrogen, halogen, C₁ to C₁₂ alkyl, and C₁ to C₁₂ alkoxy.
 2. The compound of claim 1 wherein X is hydrogen, R₁ is methyl and R₂ is t-octyl. 